#ifndef THREADS_THREAD_H
#define THREADS_THREAD_H

#include <debug.h>
#include <list.h>
#include <stdint.h>
#include "threads/fixed_point.h" //任务3 的浮点数运算

/* States in a thread's life cycle. 线程状态 */
enum thread_status
  {
    THREAD_RUNNING,     /* 运行；Running thread. */
    THREAD_READY,       /* 就绪；Not running but ready to run. */
    THREAD_BLOCKED,     /* 阻塞；Waiting for an event to trigger. */
    THREAD_DYING        /* 销毁；About to be destroyed. */
  };

/* Thread identifier type.
   You can redefine this to whatever type you like. */
typedef int tid_t;
#define TID_ERROR ((tid_t) -1)          /* Error value for tid_t. */


/* Thread priorities.线程优先级 */

#define PRI_MIN 0                       /* Lowest priority. */
#define PRI_DEFAULT 31                  /* Default priority. */
#define PRI_MAX 63                      /* Highest priority. */

/* A kernel thread or user process.

   Each thread structure is stored in its own 4 kB page.  The
   thread structure itself sits at the very bottom of the page
   (at offset 0).  The rest of the page is reserved for the
   thread's kernel stack, which grows downward from the top of
   the page (at offset 4 kB).  Here's an illustration:

        4 kB +---------------------------------+
             |          kernel stack           |
             |                |                |
             |                |                |
             |                V                |
             |         grows downward          |
             |                                 |
             |                                 |
             |                                 |
             |                                 |
             |                                 |
             |                                 |
             |                                 |
             |                                 |
             +---------------------------------+
             |              magic              |//检查下面两个问题的标志
             |              magic              |
             |                :                |
             |                :                |
             |               name              |
             |              status             |
        0 kB +---------------------------------+

   The upshot of this is twofold:

      线程结构不能过大；

      1. First, `struct thread' must not be allowed to grow too
         big.  If it does, then there will not be enough room for
         the kernel stack.  Our base `struct thread' is only a
         few bytes in size.  It probably should stay well under 1
         kB.

      内核栈不能过大；内核函数不应该分配大的空间结构或数组作为非静态局部变量。
      使用malloc()或palloc_get_page()进行动态分配代替。

      2. Second, kernel stacks must not be allowed to grow too
         large.  If a stack overflows, it will corrupt the thread
         state.  Thus, kernel functions should not allocate large
         structures or arrays as non-static local variables.  Use
         dynamic allocation with malloc() or palloc_get_page()
         instead.

   The first symptom of either of these problems will probably be
   an assertion failure in thread_current(), which checks that
   the `magic' member of the running thread's `struct thread' is
   set to THREAD_MAGIC.  Stack overflow will normally change this
   value, triggering the assertion. */

   /*elem两个用途，运行队列和信号量等待队列；原因是只有处于就绪态的线程
   会在运行队列，只有处于阻塞态的线程会在信号量等待队列。*/

/* The `elem' member has a dual purpose.  It can be an element in
   the run queue (thread.c), or it can be an element in a
   semaphore wait list (synch.c).  It can be used these two ways
   only because they are mutually exclusive: only a thread in the
   ready state is on the run queue, whereas only a thread in the
   blocked state is on a semaphore wait list. */
struct thread
  {

     // 加两个任务3用的东西
     int nice; //代表线程对其他线程的友好程度
     fixed_t recent_cpu; // 每一个线程都拥有的变量，反应该线程获得 cpu 的多少。

    /* Owned by thread.c. */
    tid_t tid;                          /* 标识符id；Thread identifier. */
    enum thread_status status;          /* 状态；Thread state. */
    char name[16];                      /* Name (for debugging purposes). */
    uint8_t *stack;                     /* 栈指针；Saved stack pointer. */
    int priority;                       /* 优先级；Priority. */
    struct list_elem allelem;           /* 用于所有线程的队列连接；List element for all threads list. */
    int64_t thread_sleep_tick;          /*记录线程被阻塞的时间 problem1*/
// origin/zcx
    /* Shared between thread.c and synch.c. */
    struct list_elem elem;              /* 共享于thread.c和synch.c之间的；在thread.c中基本是就绪队列（&ready_list）
    中的元素连接而在synch.c中是信号量等待队列（&semaphore.waiters）中的元素连接List element. */

#ifdef USERPROG
    /* Owned by userprog/process.c. */
    uint32_t *pagedir;                  /* Page directory. */
#endif

    /* Owned by thread.c. */
    unsigned magic;                     /* thread_current()里面断言判断这个；Detects stack overflow. */
    int64_t ticks_blocked;//记录线程被阻塞的时间。
    //需要能记录线程被谁捐赠了，还有在等谁的锁
    int base_priority;//线程未被捐赠时的优先级
    struct list locks;//线程把持的锁
    struct lock *lock_waiting;//线程现在等待的锁

  };

/* If false (default), use round-robin scheduler.
   If true, use multi-level feedback queue scheduler.
   Controlled by kernel command-line option "-o mlfqs". */

extern bool thread_mlfqs; //默认false轮循调度程序；true时多级反馈队列调度程序；


void thread_init (void);
void thread_start (void);

void thread_tick (void);
void thread_print_stats (void);

typedef void thread_func (void *aux);
tid_t thread_create (const char *name, int priority, thread_func *, void *);

void thread_block (void);
void thread_unblock (struct thread *);

struct thread *thread_current (void);
tid_t thread_tid (void);
const char *thread_name (void);

void thread_exit (void) NO_RETURN;
void thread_yield (void);

/* Performs some operation on thread t, given auxiliary data AUX. */
typedef void thread_action_func (struct thread *t, void *aux);
void thread_foreach (thread_action_func *, void *);

int thread_get_priority (void);
void thread_set_priority (int);

int thread_get_nice (void);
void thread_set_nice (int);
int thread_get_recent_cpu (void);
int thread_get_load_avg (void);
void blocked_thread_check (struct thread *t, void *aux UNUSED);

void handle_for_advanced_scheduler(void); //problem3

bool thread_cmp_priority (const struct list_elem *a, const struct list_elem *b, void *aux UNUSED);//线程比较函数
//-----------------------------优先级捐献相关函数----------------------------
void thread_hold_the_lock(struct lock *lock);//该线程持有该锁相关更新
void thread_donate_priority (struct thread *t);//执行线程优先级捐献
void thread_update_priority (struct thread *t);/* 优先级捐献相关更新 */
void thread_remove_lock (struct lock *lock);/* 释放锁时进行的优先级还原操作 */


#endif /* threads/thread.h */
